Aspects of the biocontrol activity of Aureobasidium spp. strain against Penicillium expansum of apple

Abstract Penicillium expansum is a fungal pathogen of pome fruit, causing the economically important disease of apple blue mould. The fungus is also important due to its ability to produce the mycotoxin patulin. A strain of Aureobasidium spp. (UC14) was assessed for controlling P. expansum and patulin production in a series of in vitro antibiosis experiments. Volatile and non‐volatile metabolites reduced growth of P. expansum on average by 50%. To assess UC14 efficacy on apples in vivo, different concentrations of cellular suspension were assayed. The concentration 1 × 10 8 cells/mL was the most effective, completely suppressing apple fruits blue mould symptoms. The antagonism of UC14 was further demonstrated by the very low amount of pathogen DNA in treated fruits detected by qPCR. During cold storage, Aureobasidium strain UC14 persisted on fruits and reduced disease severity by 82.5% and 89.8%, for ‘ Golden delicious ’ and ‘ Fuji ’ apples, respectively. Aureobasidium strain UC14 reduced patulin on ‘ Golden delicious ’ and ‘ Fuji ’ apples by 98.1% and 96.2% with respect to the control, demonstrating good efficacy as a potential biological control agent (BCA), so becoming an interesting candidate for use as BCA in the postharvest phase.